Friction device for a moving web



M. ALDEN FRICTION DEVICE FOR 'A MOVING was March 24, 1959 Filed May 24. 19 54 mmw wflm 0 JP, 2% J. Z M? jerking.

FRICTION DEVICE FOR A MOVING WEB Milton Alden, Needham, Mass.

Application May 24, 1954, Serial No. 431,866

11 Claims. (Cl. 271-215) In the art of feeding webs past a feeding station such as a coating, printing or recording station it is often necessary to maintain a very steady movement of the web to prevent irregular treatment thereof. For example in recording facsimile signals a web of sensitive paper is 1 drawn by feed rolls from a supply roll and thence between a pair of marking electrodes one of which effectively scans across the web transversely of the direction of web feed. While the feed rolls may operate very steadily, the portions of the web in advance of the feed rolls will often 4 .to detect by observation of the feeding rate are nevertheless readily apparent as transverse gaps in the facsimile .record on the paper. Thus it is highly desirable that the paper be fed at a uniform speed without hitching or It is also highly desirable to apply a uniform stretch to moist electrolytic paper so that in drying it will not contract irregularly and distort the record marked thereon. While a drag may be applied to the supply roll, its shaft or other support or two idler rolls engaging the web thereby tending to retard the web, the drag, though critically controlled, is usually as irregular as in the case of an unretarded web. Drag on the supply roll will vary as the roll decreases in diameter. Drag applied to idler rolls is variable owing in part to the ineffectiveness of the line contact between the web and the rolls. 7

Accordingly objects of the present invention are to apply a uniform, self-adjusting pressure which is not critical in nature, which is applied over a large area in comparison with the line contact of a pair of idler rolls, and which isolates the portions of the web at the recording station from any tendency of the supply roll to impart uneven movement to the web. A further object is to prevent the scanning electrode or other treating means from causing the paper to become wrinkled or to flutter due to the particular treatment. I

In a broad aspect the invention involves apparatus comprising means for holding a web roll, means for feeding the web lengthwise along a path from the holding means, means adjacent said path for treating the web, means forming a curved path for the web between said holding and treating means, and a friction member yieldingly urging said web against said curved path forming means, the friction member including an element extending substantially entirely across said web and means tiltably mounting the friction element relative to the curved path forming means so that the element may angularly adjust to the path of the web.

Preferably the friction element conforms to an area of the path forming means and accordingly may comprise a flexible membrane extending substantially en- United States Patent tirely across the web and a substantial distance lengthwise 2,879,061 Patented Mar. 24, 1959 of the web. In a more specific aspect the friction member comprises a mounting portion slidingly fitted in a socket and a frame carrying the friction element, the frame being movably attached to the mounting portion to tilt about an axis parallel to the elongate friction element, and preferably about an axis perpendicular to the first said axis.

For the purpose of illustration a typical embodiment of the invention is shown in the accompanying drawing in which:

Fig. 1 is a side elevation of facsimile recording apparatus, one side wall of the housing for said apparatus being omitted; and

Fig. 2 is an isometric view of a friction member adapted to be detachably mounted in the housing of Fig. 1.

As shown in Fig. 1 the facsimile apparatus comprises a housing including a base 1 and a cover 2 hinged to the base at 3. Within the base 1 a supply roll 4 of electrolytic recording paper W is rotatably supported on a shaft 6. The electrolytic paper web W is drawn from the supply roll 4 by a drive roll 7 and a mating roll 8. After leaving the supply roll W the web is drawn over a curved plate 9, or as shown in my United States Patent 2,655,427, a roller. The web then passes between a helical electrode 11 carried on a drum 12 supported in the base -1 on an axle 13. Opposed to the helical electrode 11 is a loop blade electrode 14 which has a straight portion 15 extending transversely of the web W and pressing the web toward the helical electrode 11. As is more fully disclosed in my above-mentioned patent, facsimile signals are applied between the helical electrode 11 and the blade electrode 14 so that as the helical electrode effectively scans along the recording edge 15 a current is passed between the electrodes and through the paper thereby marking the signals on the web. I The loop electrode 14 and its drive motor 16 are supported on a bracket 17 which fits in a socket formed by two leaf springs 18 mounted in the cover 2. The drive motor 16 continually orbits the loop electrode 14 so that the effective recording edge 15 does not become unevenly eroded due to electrolytic deposition on the web W. p

A similar socket in the cover 2 is formed by a leaf spring 21 and a flange 22 for receiving the mounting portion 23 of a friction member 20. As shown in Fig. 2 the friction member 20 includes a frame 24 having spaced parallel edges 26 and 27 between which is stretched a flexible membrane 28 of rubberized fabric or similar flexible sheet material. The membrane 28 is attached to the frame 24 by clamping strips 29. The frame 24 has a pair of ears 31 at its opposite ends. Formed in the ears 3]. are elongated guide slots 32 generally extending away from the membrane 28. On the mounting portion 23 are two pins 33 which loosely engage in the guide slots 32 thereby loosely attaching the frame 24 to the mounting member 23. The frame 24 is free to pivot about a first axis I extending approximately through the axis of the pins 33 parallel to the elongate dimension of the membrane 28. The frame 24 is further capable of pivoting or tilting about a second axis II perpendicular to the first axis I by virtue of the loose or sliding engagement of the pins 33 in the guide slots 32. A pair of elbow shaped levers 34 are pivotally attached to the mounting portion 23 by rivets 36. One end 34a of the levers 34 extends into engagement with the frame 24, while the other end 34b is coupled to a coil spring 37 which is looped about a post 38. Engagement of the lever ends 34a against the frame 24 causes the levers yieldingly to oppose rotation about the first axis I and the second axis II as well. If in tilting about the second axis II one end of the frame 24 moves toward the mounting portion 23 more than the other end, one of the levers 36 will be rotated more. thanthenother lever,

thereby tending to increase the tension on that portion of the coil spring between it and the post 38. However this increased tension will be transmitted by the spring around the post 38 to the other lever thereby equalizing the pressure with which both levers press on the frame 24.

When the friction member 20 of Fig. 2 is inserted in the cover socket 21-22 the frame 24 and membrane 28 are yieldingly urged against the curved plate 9 thereby pressing the web W against the curved plate. By virtue of its flexible nature the membrane 28 will assume a convex shape and conform to a substantial area of the plate 9 thereby applying a frictional retarding force to the web over an area extending substantially completely transversely of the web and also extending a substantial distance along the direction of web feed. Whether the; friction member 20 is properly mounted in its socket 21-22, or whether the plate 9 is accurately positioned the frame 24 will make such tilting adjustment as is necessary to engage all portions of the contact area on the web with equal pressure. Because the frame 24 is yieldingly urged toward the plate 9 with a moderate pressure which coupled with the frictional effect of the membrane 28 supplies a back tension to the web W, this tension being distributed across the web stretches and smooths the web as it passes between the electrodes 11 and 14. The back tension damps any tendency of the helical electrode 11 to cause the paper to bounce or flutter or to feed unevenly. The effect of irregular rotation of the supply roll is thereby eliminated. As shown in Fig. 1 the path of the web W swings relatively to the plate 9 to a new path W as the diameter of the supply roll 4 decreases. This change in the path of the web is accommodated by tilting of the frame 24 about its first axis I generally parallel to the length of the membrane 28 so that even pressure of the contact area is maintained. It has been found that the present friction member so effectively isolates that portion of the web W at the recording staton between the electrodes 11 and 14 from irregular movement imparted by the supply roll 4 that the supply roll need not be mounted on the shaft 6 but may be dropped loosely into the base 1.

I claim:

1. In the art of treating an elongate web, apparatus comprising means for holding a web roll, means for continuously feeding the web lengthwise along a path from said holding means, means adjacent said path for treating said web, means forming a curved path for the web between said holding and treating means, and a friction member yieldingly urging said web against said curved path forming means including a friction element extending and adapted to apply an even frictional drag substantially entirely across said web thereby to apply back tension on the web, said member including means tiltably mounting said element relative to said curved path forming means so that said element may angularly adjust to the path of the web without substantially altering the pressure or tension of said element on the web.

2. In the art of recording on an elongate web, apparatus comprising means for holding a web roll, means for continuously feeding the web lengthwise along a path from said holding means, marking means adjacent said path for contacting and marking on said web, means forming a curved path for the web between said holding and marking means, and a friction member yieldingly urging said web against said curved path forming means including a friction element extending and adapted to apply an even frictional drag substantially entirely across said web and conformable to an area of said path forming means thereby to apply back tension on the web, said member including means tiltably mounting said element relative to said curved path forming means so that said element may angularly adjust to the path of the web without substantially altering the pressure or tension of said element on the web.

3. In the art of recording on an elongate web, apparatus comprising means for holding a web roll, means for continuously feeding the web lengthwise along a path from said holding means, marking means adjacent said path for contacting and marking on said web, means forming a curved path for the web between said holding and marking means, and a friction member yieldingly urging said Web against said curved path forming means including a flexible membrane extending and adapted to apply an even frictional drag substantially entirely across said web and conformable to an area of said path forming means thereby to apply back tension on the web, said area extending a substantial distance lengthwise of the web without substantially altering the pressure or tension of said element on the web.

4. In the art of recording on an elongate web, apparatus comprising means for holding a web roll, means for continuously feeding the web lengthwise along a path from said holding means, said web roll decreasing in diameter as the web is fed therefrom so as to change said path, marking means adjacent said path for contacting and marking on said web, means forming a curved path for the web between said holding and marking means, and a friction member yieldingly urging said web against said curved path forming means including a flexible membrane extending and adapted to apply an even frictional drag substantially entirely across said web and conformable to an area of said path forming means thereby to apply back tension on the web, said area extending a substantial distance lengthwise of the web, and said member including means tiltably mounting said membrane relative to said curved path forming means so that said membrane may angularly adjust to the path of the web without substantially altering the pressure or tension of said element on the web as said path changes.

5. In the art of recording on an elongate web, apparatus comprising a support, means on the support for holding a web roll, means on the support for continuously feeding the web lengthwise along a path from said holding means, marking means on the support adjacent said path for contacting and marking on said web, means on the support forming a curved path for the web between said holding and marking means, and a friction member yieldingly urging said web against said curved path forming means, said member including a frame tiltably mounted on the support and having spaced edges extending transversely of the path and a flexible membrane supported by and between said edges so as to extend and adapted to apply an even frictional drag substantially entirely across said web and conform to an area of said path forming means thereby to apply back tension on the web, said area extending a substantial distance lengthwise of the web without substantially altering the pressure or tension of said element on the web.

6. In the art of recording on an elongate web, apparatus comprising a support, means on the support for holding a web roll, means on the support for continuously feeding the web lengthwise along a path from said holding means, marking means on the support adjacent said path for contacting and marking on said web, means on the support forming a curved path for the web between said holding and marking means, means forming a socket in said support, and a friction member on the support yieldingly urging said Web against said curved path forming means including a mounting portion slidinging fitting in said socket and a flexible membrane extending and adapted to apply an even frictional drag substantially entirely across said web and conformable to an area of said path forming means thereby to apply back tension on the web, said area extending a substantial distance lengthwise of the web.

7. In the art of recording on an elongate web, apparatus comprising a relatively movable cover and base, means in the base for holding a web roll, means in the base for continuously feeding the web lengthwise along a path from said holding means, cooperative marking means in said base and cover adjacent said path for contacting and marking on said web, means in the base forming a curved path for the web between said holding and marking means, means forming a socket in said cover, and a friction member for yieldingly urging said web against said curved path forming means including a mounting portion slidingly fitting in said socket, a frame and an elongate friction element on said frame extending and adapted to apply an even frictional drag substantially entirely across and bearing on said web and conformable to an area of said path forming means thereby to apply back tension on the web, said frame being movably attached to said mounting portion to tilt about an axis parallel to said elongate element without substantially altering the pressure or tension of said element on the web.

8. In the art of recording on an elongate web, apparatus comprising a relatively movable cover and base, means in the base for holding a web roll, means in the base for continuously feeding the web lengthwise along a path from said holding means, cooperative marking means in said base and cover adjacent said path for contacting and marking on said web, means in the base forming a curved path for the web between said holding and marking means, means forming a socket in said cover, and a friction member for yieldingly urging said web against said curved path forming means including a mounting portion slidingly fitting in said socket, a frame and an elongate friction element on said frame extending and adapted to apply an even frictional drag substantially entirely across and bearing on said web and conformable to an area of said path forming means thereby to apply back tension on the Web, said frame being movably attached to said mounting portion to tilt about an axis parallel to said elongate element and about an axis perpendicular to the first said axis without substantially altering the pressure or tension of said element on the web.

9. Apparatus'for treating an elongate web comprising a curved guide, means for feeding the web along a predetermined path including a curved portion over said guide, and a web tensioning device at said curved portion opposite said guide, said device including a frame and a flexible membrane connected at both of its ends to said frame, the membrane bearing on the convex side of the web throughout an area extending throughout a substantial part of said curved portion, and means for yieldingly pressing the membrane against the web.

10. For retarding a Web fed on a changing path, a friction member comprising a mounting portion, a frame movably attached thereto, an elongate friction element on said movable frame for bearing on and retarding said web, guide means on the frame forming elongate openings spaced lengthwise of said element and extending away from said element, attaching means on the mounting portion loosely engaging in said openings respectively to permit the frame and friction element to tilt about an axis extending between said openings and about an axis perpendicular to the first said axis, a pair of levers pivoted on said mounting portion, and spring means yieldingly urging one end of said levers respectively against portions of said frame spaced lengthwise of said element thereby yieldingly opposing tilting of the frame about said axes.

11. For retarding a web fed on a changing path, a friction member comprising a mounting portion, a frame movably attached thereto, an elongate friction element on said movable frame for bearing on and retarding said web, guide means on the frame forming elongate openings spaced lengthwise of said element and extending away from said element, attaching means on the mounting portion loosely engaging in said openings respectively to permit the frame and friction element to tilt about an axis extending between said openings and about an axis perpendicular to the first said axis, a pair of levers pivoted on said mounting portion, spring means yieldingly urging one end of said levers respectively against por tions of said frame spaced lengthwise of said element thereby yieldingly opposing tilting of the frame about said axes, said spring means being attached to both levers, and means holding said spring means in a loop so as to balance the tension on said levers respectively.

References Cited in the file of this patent UNITED STATES PATENTS 917,727 Hammond Apr. 6, 1909 1,539,754 McCullougho May 26, 1925 2,398,822 Faris et a1 Apr. 23, 1946 2,574,002 Weiss Nov. 6, 1951 2,647,033 Faus July 28, 1953 2,655,427 Alden Oct. 13, 1953 

